I've got no idea how many miles I've driven in my life, but probably in
the neighborhood of about 350,000. In all that time, I've seen wheels
lost--by other people--twice. Once was on a freeway in California, I was
headed north, they were headed south on the other side. I remember seeing
the wheel bouncing down the southbound lanes as the car it came of at came
to an abrupt halt. The other was when a wheel fell off a boat trailer.

I've seen the explosive failure on large trucks (lorries) twice just in
the last 5 years. Big tires, big bang with lots of noise.

US drivers commonly see the fallen off tread from failed retread tires.
You probably can't drive 50 miles without seeing that.

I remember my parents having Chrysler cars in the 1960 with the left- and
right-hand wheel nuts. I remember being told that it was that way because
of tire rotation it would tend to tighten loose wheel nuts rather than
loosen them. It would be interesting to analyze when wheels do fall off do
they tend to fall off the same side?? (thus, arguing for going back to the
left- and right-hand format).

This is strange; I talked to a number of people, and nobody knows
anyone, or knows anyone who heard of anyone who has ever lost a wheel
while driving. At least in Germany. I can't recall a single case being
reported in the newspapers. Maybe shop procedures are better over here.

Having a tyre fail is much more common, and almost everyone either had
it happen to him or knows someone directly to whom it happened. Either
complete (slow) deflation, explosive failure (rare) or losing parts of
the tread (especially on retreaded tyres. Happened to my wife, and it
was the last time we ever bought retreaded).

I heard of the Chrysler way (maybe some German manufacturers also did
it?), but it just didn't seem to be worth the hassle because if
tightened properly, wheel nuts just didn't fail.